De. Pearson et al., Small mammal communities and habitat selection in Northern Rocky Mountain bunchgrass: Implications for exotic plant invasions, NW SCI, 75(2), 2001, pp. 107-117
Agriculture and development have dramatically reduced the range of native b
unchgrass habitats in the Northern Rocky Mountains, and the invasion of exo
tic plants threatens to greatly alter the remaining pristine prairie. Small
mammals play many important roles in ecosystem functions, but little is kn
own about small mammal community composition and structure in native bunchg
rass habitats of the Northern Rocky Mountains. We live trapped small mammal
s along transects to study community composition, relative abundance, and h
abitat relationships in three native bunchgrass sites of west-central Monta
na. Small mammal community composition and relative abundance were consiste
nt among sites, with deer mice (Peromyscus maniculatus) dominating, followe
d by montane voles (Microtus montanus), which were uncommon, and montane sh
rews (Sorex monticolus). which were rare. Deer mice and montane voles exhib
ited complementary habitat separation. Deer mice tended to select open micr
osites and avoid sires with high percentages of vegetative cover. Male and
female deer mice demonstrated strong habitat separation at two sites, but t
he habitat variables partitioned between sexes differed by site. Montane vo
les avoided open sites and selected for concave microsites where the vegeta
tive cover was relatively dense. This information provides an important bas
eline for understanding pre-settlement small mammal communities in the rapi
dly dwindling, native bunchgrass habitats of the Northern Rocky Mountains.